The practical limits for enhancing magnetic property combinations for bulk nanocrystalline NdFeB alloys through Pr, Co and Dy substitutions

Pr, Co and Dy additions have been employed to improve the combinations of magnetic properties for nanocrystalline NdxFe94−xB6 melt spun alloys. The dependences of the magnetic properties on the solute element concentrations have been extensively investigated and the relationships between the measured remanence, maximum energy product (BH)max and intrinsic coercivity for several compositional series are discussed. The composition ranges for these elemental substitutions which can be used to achieve the highest values of (BH)max are identified. It is found that, when we employ individual or combined substitutions of Pr and Dy for Nd and Co for Fe in NdFeB alloys with various RE:Fe ratios, the practical limit of (BH)max lies in the range ∼160–180 kJ/m3, combined with a coercivity in the range ∼400–800 kA/m.